Mesomorphic and themochmical behavior of a Cu(II)-cyclam ionic liquid: A novel approach to metallomesogens

The metalomesogenic compounds exhibit captivating optical, magnetic, and electrical characteristics makes promising candidates for diverse applications in the fields of display devices, sensors, and molecular electronics. In this study, we focused on synthesizing the dark-purple powder of metallomesogen [Cu(Cy)(L)2](X)2.2H2O, where Cy represents cyclam (1,4,8,11-tetraazacyclotetradecane), X is 4-BrC6H4COO-, and L is 4-Hexadecyloxypyridiene. The synthesis process involved four distinct steps. Differential scanning calorimetry (DSC) analysis revealed phase transitions at 42.3 °C (crystal-to-mesophase), 81.3 °C (mesophase-to-mesophase), and 111.7 °C (mesophase-to-isotropic liquid). Polarized optical microscopy (POM) confirmed the formation of characteristic optical textures upon cooling, indicative of a stable mesophase at 78.0 °C. The magnetic susceptibility measurements showed a magnetic moment of 1.7 Bohr magnetons, consistent with a mononuclear copper complex in a distorted octahedral geometry. These findings demonstrate the potential of this metallomesogen for applications in advanced display devices and sensors. KEY WORDS: Metallomesogens, Ionic liquid, Cyclam, 4-Hexadecyloxypyridiene, Copper Bull. Chem. Soc. Ethiop. 2025, 39(7), 1381-1394. DOI: https://dx.doi.org/10.4314/bcse.v39i7.11